Acetylene-terminated polyimide oligomers show promise as matrix resins for advanced aircraft and aerospace systems. The materials have the potential of curing without the evolution of volatile by-products, thereby obviating the problem of void formation in composite structures and molded articles. Unfortunately, the oligomers normally contain residual amounts of the solvent employed in their synthesis. During curing operations, voids are formed in the composites or molded objects as a result of the volatilization of the residual solvent.
It is a principal object of this invention, therefore, to purify acetylene-terminated polyimide oligomers by removing residual solvent therefrom.
Other objects and advantages of the invention will become apparent to those skilled in the art upon consideration of the accompanying disclosure.